So the problem seems to be that mergeInMembers( alreadyExistingMetaEntity.getMembers() ); undermines the effect of lazily initializing the members, i.e. the members of the embeddable ZeroCoordinates are built-up before we know the access type as determined by the embedding entity. I gues the merging would also have to happen in a lazy manner.

Hardy Ferentschik: I'm starting to wonder about the test set up, though. As per the annotation on the embedding entity Location, field access type is to be used. Still in coordinates.xml two attributes are configured for ZeroCoordinates which actually don't exist with the required access type. Does this configuration make sense at all?